Multi position rotary detent device

ABSTRACT

A multi position rotary detent device in which a plurality of detent positions are available with each position determined by discrete magnetic fields established between rotor pole pieces and stator pole pieces and in which selected detent positions can be achieved by rotation of the rotor to establish magnetic fields between selected rotor pole pieces and selected stator pole pieces.

United States Patent 1191 UNITED STATES PATENTS Howell 310/156 Ward Dec. 17, 1974 [54] MULTI POSITION ROTARY DETENT 3,344,378 9/1967 Wilhelmson 335/272 DEVICE 3,473,061 10/1969 Soehner 310/156 [75] Inventor: Frank L. Ward, Kensington, N.1-1. FOREIGN PATENTS OR APPLICATIONS [73] Assigneez Clamstat Mfg. Inc. Ddver, 884,471 12/1961 Great Br1ta1n 310/156 Primary Examiner-G. Harris [22] Filed: May 14, 1973 [21] App]. No.: 360,138 ABSTRACT l A multi position rotary detent device in which a plu- 521 US. Cl 335/302 310/156 335/253 ramy of i i are availablfi with each I 51 1m. 01. .1 1 1011 7/02 determined by discrete magnetic fields [58] Field of Search 335/229, 230 272 279, lished between rotor pole pieces and stator po1e pieces 335/302, 310/49 103 156 and in which selected detent positions can be achieved by rotation of the rotor to establish magnetic fields be- [56] References Cited tween'selected rotor pole pieces and selected stator pole pieces.

8 Claims, 4 Drawing Figures MULTI POSITION ROTARY DETENT DEVICE BACKGROUND OF THE INVENTION A detent device is one in which a moving part thereof is stoppeddue to the action of the devicein a predetermined position. A multi position rotary detent device is one in which a part which is capable of rotary movement is'provided with a number of stopping points each being a detent position. The stopping pointin a detent device is not a positive stop but one in which an additional amount of energy or force must be utilized in order to move out of that position.

Detent devices in various configurations are well known in the art. A detent device which is stopped or which has its detent positions determined by mechanical action has a relatively short life due to the frictional engagement of parts. It is important in'manyaapplications to have a relatively simple .detent device which is capable of long life and one which is'not subject to severe wear due to frictional engagement of parts.

SUMMARY OF THE INVENTION A multi position rotary detent device iri-which spaced stator and rotor members are provided with means for developing discrete zones of magnetic flux establishing detent positions and the angular position of a shaft projecting from the. rotor determines the magnetic flux paths betweenselected zones.

DESCRIPTION -THE DRAWINGS DESCRIPTION OF THE INVENTION A multi position detent device constructed in accordance with the inventionis shown in FIGS. 1 and 2 and indicated by the numeral 10. Stator 11 of the device includes a circular disk base 12 having a plurality of circularly arranged teeth 13 formed integrally therewith projecting axiallyand radially inwardly. In the embodiment shown in FIGS. 1 and 2 there are 24 such teeth or pole pieces. The stator .is formed of a magnetic material, such as low carboncontent, iron or steel. If the teeth are not formed integral with the base a nonmagnetic material is preferred for the base 12.

In the embodiment of FIGS. 1 and 2 a bushing 14 is formed integral with the base and rotatably supports non-magnetic shaft 15. Flat Washer 16 is also used in this embodiment spacing the rotor 17 from the stator 11.

The shaft is provided with a flattened surface portion or keyway 18 upon which the rotor is mounted so that the rotor cannot rotate relative to shaft 15. Cylindrical disk magnet '19 is provided in the rotor with the surface 19' oriented magnetic north and the surface 19" oriented magnetic south. A first rotor pole mem- 2 ber'20 is provided adjacent surface l9'1and a like rotor pole member 21-is provided adjacent magnet surface 19". Each of the polemembers has a disk body similarto that of magnet 19 but with pole pieces projecting radially outwardly therefrom, hence, as seen in the FIGS.

' pole member is provided with pole pieces 20 pro- .jecting radially outwardly therefrom while pole member 21 is provided with pole pieces 21 projecting outwardly therefrom.

Since pole member 20 is adjacent surface 19' of the magnet which is oriented magnetic north the pole member ,and hence the pole pieces 20 are oriented magnetic north, and likewise pole member 21 is oriented magnetic south as are pole pieces 21' oriented magnetic south. The pole members as are the pole pieces 13 of the stator are formed of a magnetic material.

It is noted that the diameter of'the magnet is less than the diameter of either of the pole members and that each stator pole piece is a discrete rectangular member having an inwardly facing edge which in the detent position extends from one of the rotor pole pieces of the first pole member to one of the pole pieces of the second pole member while spanning the magnet.

In the position of the rotor with respect to the stator that is shown in the FIGS. 1 and 2 the device is considered to be in the detentposition and there are magnetic flux paths established between selected rotor pole pieces or pairs of selected rotor pole pieces and a stator pole piece. Hence as seen in FIG. 1 in this particular detent position the flux path X is established by the pole pieces 20a, 21a and 13a. Also a flux path by way of example, is established by pole pieces 20b, 21b and 13b. The selected path is determined by the angular position of shaft 15. Rotation of shaft 15 if desired, could establish new flux paths so that by way of example, a flux path would be determined by pole pieces 20a, 21a and 13b. Upon the establishment of a flux path a detent position is determined.

In FIGS. 3 and 4 an alternate embodiment of the invention is shown in whichthe rotor is identical to the rotor of the embodiment of FIGS. 1 and 2 but the stator is of different configuration.

Hence in FIGS. 3 and 4 rotor 117 consisting of magnet 119 and rotor members 120 and 121 is identical to rotor 17 consisting of magnet 19 and pole members 20 and 21 and mounted upon shaft 115 which is rotatably supported in bushing 114 of base 112 of stator 111. The rotor is mounted on the fiat 118 of the shaft 115 and washer 116 is provided for spacing;

The stator in this embodiment differs from the stator of the first embodiment in the structure of the pole pieces. In this embodiment the stator has a generally circular wall of magnetic material and serpentine configuration surrounding the rotor with the inwardly directed crests 131 thereof respectively providing stator pole pieces. As in the first embodiment, each of the stator pole pieces can extend from one of the pole pieces of the rotor to another while spanning the magnet. The serpentine wall 130 can also be formed integralwith base 112 and in the embodiment shown in FIGS. 3 and 4 there are 24 inwardly directed crests 131 providing 24 stator pole pieces to cooperate with 24 pairs of rotor pole pieces in the manner in which the pole pieces cooperate in the first embodiment as described above.

I claim:

l. A multi position rotary detent device including in combination a first rotary member, a plurality of circularly arranged first pole pieces of said first rotary memher, said first pole pieces being formed of a magnetic material, a second rotary member rotatably supported with respect to said first rotary member, a magnet of said second rotary member having first and second surfaces respectively oriented magnetic north and magnetic south, a first pole member of said second rotary member adjacent said first surface and having second pole pieces, a second pole member of said second rotary member adjacent said second surface and having third pole pieces, said pole members being in fixed relation with said magnet and formed of a magnetic material, said second and third pole pieces and said first pole pieces projecting toward each other, and means for relatively rotating said first and second rotary members whereby the relative angular position of said first rotary member with respect to said second rotary member determines the magnetic flux paths between selected second and third pole pieces and selected said first pole pieces.

2. A multi position rotary detent device including in combination a stator, a stator base of said stator formed with a plurality of circularly arranged stator pole pieces, said stator pole pieces being formed of a magnetic material, and a bushing formed on said stator base; a shaft rotatably supported in said bushing on the axis of said stator, said shaft being formed of a nonmagnetic material; a rotor supported by said shaft in fixed relation with respect thereto, a magnet of said rotor having first and second surfaces respectively oriented magnetic north and magnetic south, a first rotor pole member adjacent said first surface and having first rotor pole pieces projecting radially outwardly therefrom, a second rotor pole member adjacent said second surface and having second rotor pole pieces projecting radially outwardly therefrom, said pole members being formed of a magnetic material and whereby the angular position of said shaft determines a plurality of magnetic dance with claim 2 in which said stator pole pieces are formed integral with said stator base.

7 4. A multi position rotary detent device in accordance with claim 2 in which said magnet is a circular disk and said pole members are disks with said rotor pole pieces projecting outwardly respectively in the planes thereof and the diameter-of said magnet is less than the diameter of either of said pole members.

5. A multi position rotary detent device in accordance with claim 2 in which each of said stator pole pieces projects axially of said stator.

6. A multi position rotary detent device in accordance with claim 5 in which each of said stator pole pieces is a discrete rectangular member having an in wardly facing edge which in the detent position extends from one of said first rotor pole pieces to one of said second rotor pole pieces while spanning said magnet.

7. A multi position rotary detent device in accordance with claim 5 in which said stator has a generally circular wall of serpentine configuration surrounding said rotor with the inwardly directed crests thereof respectively providing the stator pole pieces and wherein each stator pole piece in the detent position extends from one of said first rotor pole pieces to one of said second rotor pole pieces while spanning said magnet.

8. A multi position rotary detent device in accordance with claim 2 in which each of said first rotor pole pieces forms a pair with one of said second rotorpole pieces and there are the same number of pairs so pro vided as are stator pole pieces. 

1. A multi position rotary detent device including in combination a first rotary member, a plurality of circularly arranged first pole pieces of said first rotary member, said first pole pieces being formed of a magnetic material, a second rotary member rotatably supported with respect to said first rotary member, a magnet of said second rotary member having first and second surfaces respectively oriented magnetic north and magnetic south, a first pole member of said second rotary member adjacent said first surface and having second pole pieces, a second pole member of said second rotary member adjacent said second suRface and having third pole pieces, said pole members being in fixed relation with said magnet and formed of a magnetic material, said second and third pole pieces and said first pole pieces projecting toward each other, and means for relatively rotating said first and second rotary members whereby the relative angular position of said first rotary member with respect to said second rotary member determines the magnetic flux paths between selected second and third pole pieces and selected said first pole pieces.
 2. A multi position rotary detent device including in combination a stator, a stator base of said stator formed with a plurality of circularly arranged stator pole pieces, said stator pole pieces being formed of a magnetic material, and a bushing formed on said stator base; a shaft rotatably supported in said bushing on the axis of said stator, said shaft being formed of a non-magnetic material; a rotor supported by said shaft in fixed relation with respect thereto, a magnet of said rotor having first and second surfaces respectively oriented magnetic north and magnetic south, a first rotor pole member adjacent said first surface and having first rotor pole pieces projecting radially outwardly therefrom, a second rotor pole member adjacent said second surface and having second rotor pole pieces projecting radially outwardly therefrom, said pole members being formed of a magnetic material and whereby the angular position of said shaft determines a plurality of magnetic flux paths, each of said flux paths being between selected first and second pole pieces and selected stator pole pieces which provides the magnetic circuit of said flux path.
 3. A multi position rotary detent device in accordance with claim 2 in which said stator pole pieces are formed integral with said stator base.
 4. A multi position rotary detent device in accordance with claim 2 in which said magnet is a circular disk and said pole members are disks with said rotor pole pieces projecting outwardly respectively in the planes thereof and the diameter of said magnet is less than the diameter of either of said pole members.
 5. A multi position rotary detent device in accordance with claim 2 in which each of said stator pole pieces projects axially of said stator.
 6. A multi position rotary detent device in accordance with claim 5 in which each of said stator pole pieces is a discrete rectangular member having an inwardly facing edge which in the detent position extends from one of said first rotor pole pieces to one of said second rotor pole pieces while spanning said magnet.
 7. A multi position rotary detent device in accordance with claim 5 in which said stator has a generally circular wall of serpentine configuration surrounding said rotor with the inwardly directed crests thereof respectively providing the stator pole pieces and wherein each stator pole piece in the detent position extends from one of said first rotor pole pieces to one of said second rotor pole pieces while spanning said magnet.
 8. A multi position rotary detent device in accordance with claim 2 in which each of said first rotor pole pieces forms a pair with one of said second rotor pole pieces and there are the same number of pairs so provided as are stator pole pieces. 